An analytical approach based on the work of Wiener is taken to develop an expression for an optimum linear feedback control system that will minimize the random variations in the flux of a nuclear power reactor. The optimization criterion is the minimization of the mean-square value of these random variations. In determining the optimum control system transfer function, an acceleration constraint is placed on the control-rod drive mechanism. To demonstrate the technique presented, an optimum control system transfer function is derived for the experimental boiling water reactor (EBWR) under specified operating conditions. The changes in the mean-square value of reactor flux caused by varying acceleration constraint level is discussed. Results show that a considerable reduction in the mean-square value of the random flux variations can be obtained through external control. View full abstract»

This paper describes an all-electronic analogue of the complex plane in which singularities are positioned by potentiometor settings. Although the basic principle is old, a new method of determining the argument of a function is presented and its implementation discussed. A machine called the Pole-Zero Analogue Computer was constructed to test the method and perform various operations such as the plotting of root loci, Nichols loci and equipotential lines. Other functions which can be performed include the plotting of magnitude, logarithmic-magnitude, phase-slope and phase characteristics of filters or linear systems in general. All of these applications are discussed and test results are presented. View full abstract»

This paper describes a series of systematic steps to synthesize a multivariable controller. It is a particularly useful technique when there is required partial or full noninteraction in conjunction with invariance of certain of the outputs with respect to disturbance vectors. This is a structure oriented method where the critical plant parameters and variables are reflected in the controller structure. The resulting controller structure permits a simple final field adjustment of controller parameters during the initial operation period. In addition, these same properties allow adaptive methods that require adjustment of very few of the parameters in response to environmental or plant changes. The problems of physical realization of controller elements and of achieving the desired control specifications are handled by a technique that may operate on the structure as it is derived. These operations clearly show the alternatives available, both in structuring and in realizing elements. These features indicate that algorithms to aid the design procedure would be quite possible for use on digital computers. View full abstract»

A fairly new type of compensator for carrier control systems consists of a passive electric network that contains one or more periodically-conducting branches. This type of compensator (referred to as a demodulating compensating network) is superior to other types, used previously, in terms of size, weight, cost, and sensitivity to variations in carrier frequency. Although a detailed analysis of the operation of a demodulating compensating network is usually very tedious, it is possible to describe the effect of such a network in a feedback control system very simply by the use of an equivalent time-invariant passive electric network. A procedure for designing a phase-lead demodulating compensating network to meet specifications on system performance is presented in this paper. In essence, this procedure consists of the following steps. First, the uncompensated frequency response of the system is examined. Then an acceptable and realizable phase and/or gain characteristic is selected. Finally, by the use of design curves, the parameters of the demodulating compensator required to provide the desired frequency response are determined. Numerical examples are included to illustrate the application of the design procedure, and experimental results are reported to reveal the value of the procedure. View full abstract»

One of the major problems in missile control is the change in missile dynamics caused by changing aerodynamic parameters. The method of control described herein possesses control capability for a wide range of aerodynamic parameters utilizing only information derived from the state variables of the system. Liapunov's second method was used to derive the form of the control signal. The analysis was based on the control of an autonomous, stable plant. However, with only a slight change in the form of the signal, it was possible to stabilize a forced unstable system. The control signal was constructed by summing the weighted states of the plant and using this to trigger a bistable amplifier. The output of the bistable amplifier was summed with the command to the system. The analysis and analog computer study used a 3rd-order linearized model of typical missile dynamics. The computer study has shown that it was possible to control this model for a wide range of aerodynamic parameters. The advantages of this controller over more sophisticated adaptive control systems that might yield similar control characteristics are its simplicity and its all-electrical nature. View full abstract»

This paper is concerned with the control of two distinct th-order linear systems described in the standard state vector notation. Since both systems are of th order their state vectors can be placed in the same -dimensional phase space. A problem is formulated in which it is desired to transfer each system from separate initial states to some undetermined but coincident state (state vector rendezvous). This goal is to be accomplished in minimum time while the input vectors of both systems are amplitude constrained. Complete necessary and sufficient conditions which must be satisfied by time-optimal solutions are developed, and additionally, a technique for computing the optimum controls is given. View full abstract»

Delta modulation has often been viewed as a type of PCM and has been analyzed by probabilistic methods. This paper views delta modulation as a hybrid PDM/PAM system. A nonlinear feedback model is constructed and subjected to digital computation on an IBM 650. Computation is enabled by trapezoidal convolution, an approximate -transform method for solving dynamical systems. Responses to various steps and ramp inputs for unity and nonunity feedback are considered. Dead space is also introduced into the nonlinearity in the forward link. A series of computer runs is condensed and observations are reported. A typical observation is that a trade-off exists between average error and noise and that both may not be minimized by any one of two versions of the delta modulator. View full abstract»

In many control system applications an adaptive system is required to accommodate changes in plant dynamics. A self-adaptive system described herein adjusts two control system parameters to maintain the closed-loop response essentially constant in spite of large changes in the plant gain and pole-zero locations. The adaptive system uses a high-frequency dither frequency to interrogate the state of the control system. Two self-adaptive performance criteria (SAPC) adjust the two adaptive parameters. One SAPC is based upon the amplitude response to the dither frequency and the other is based upon the phase response. The adaptive loop associated with the amplitude SAPC adjusts the control system loop gain; the adaptive loop associated with the phase SAPC adjusts a variable compensation network. A method is developed for analyzing the stability and performance of the self-adaptive parameter adjustment loops. The stability analysis includes the interaction between these adaptive loops. This two-parameter adaptive system is applied to a specific example to illustrate the techniques developed in the paper. View full abstract»

Aims & Scope

In the IEEE Transactions on Automatic Control, the IEEE Control Systems Society publishes high-quality papers on the theory, design, and applications of control engineering. Two types of contributions are regularly considered